
/*
 *  GLM library.  Wavefront .obj file format reader/writer/manipulator.
 *
 *  Written by Nate Robins, 1997.
 *  email: ndr@pobox.com
 *  www: http://www.pobox.com/~ndr
 */

/* includes */
#include <math.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>
#include <cstdlib> // Added by dragly
#include "glm.h"


/* defines */
#define T(x) model->triangles[(x)]

/* enums */
enum { X, Y, Z, W };			/* elements of a vertex */


/* typedefs */

/* _GLMnode: general purpose node
 */
typedef struct _GLMnode {
    GLuint           index;
    GLboolean        averaged;
    struct _GLMnode* next;
} GLMnode;


/* private functions */

/* _glmMax: returns the maximum of two floats */
static GLfloat
	_glmMax(GLfloat a, GLfloat b)
{
    if (a > b)
	return a;
    return b;
}

/* _glmAbs: returns the absolute value of a float */
static GLfloat
	_glmAbs(GLfloat f)
{
    if (f < 0)
	return -f;
    return f;
}

/* _glmDot: compute the dot product of two vectors
 *
 * u - array of 3 GLfloats (GLfloat u[3])
 * v - array of 3 GLfloats (GLfloat v[3])
 */
static GLfloat
	_glmDot(GLfloat* u, GLfloat* v)
{
    assert(u);
    assert(v);

    /* compute the dot product */
    return u[X] * v[X] + u[Y] * v[Y] + u[Z] * v[Z];
}

/* _glmCross: compute the cross product of two vectors
 *
 * u - array of 3 GLfloats (GLfloat u[3])
 * v - array of 3 GLfloats (GLfloat v[3])
 * n - array of 3 GLfloats (GLfloat n[3]) to return the cross product in
 */
static GLvoid
	_glmCross(GLfloat* u, GLfloat* v, GLfloat* n)
{
    assert(u);
    assert(v);
    assert(n);

    /* compute the cross product (u x v for right-handed [ccw]) */
    n[X] = u[Y] * v[Z] - u[Z] * v[Y];
    n[Y] = u[Z] * v[X] - u[X] * v[Z];
    n[Z] = u[X] * v[Y] - u[Y] * v[X];
}

/* _glmNormalize: normalize a vector
 *
 * n - array of 3 GLfloats (GLfloat n[3]) to be normalized
 */
static GLvoid
	_glmNormalize(GLfloat* n)
{
    GLfloat l;

    assert(n);

    /* normalize */
    l = (GLfloat)sqrt(n[X] * n[X] + n[Y] * n[Y] + n[Z] * n[Z]);
    n[0] /= l;
    n[1] /= l;
    n[2] /= l;
}

/* _glmEqual: compares two vectors and returns GL_TRUE if they are
 * equal (within a certain threshold) or GL_FALSE if not. An epsilon
 * that works fairly well is 0.000001.
 *
 * u - array of 3 GLfloats (GLfloat u[3])
 * v - array of 3 GLfloats (GLfloat v[3])
 */
static GLboolean
	_glmEqual(GLfloat* u, GLfloat* v, GLfloat epsilon)
{
    if (_glmAbs(u[0] - v[0]) < epsilon &&
	_glmAbs(u[1] - v[1]) < epsilon &&
	_glmAbs(u[2] - v[2]) < epsilon)
    {
	return GL_TRUE;
    }
    return GL_FALSE;
}

/* _glmWeldVectors: eliminate (weld) vectors that are within an
 * epsilon of each other.
 *
 * vectors    - array of GLfloat[3]'s to be welded
 * numvectors - number of GLfloat[3]'s in vectors
 * epsilon    - maximum difference between vectors
 *
 */
GLfloat*
	_glmWeldVectors(GLfloat* vectors, GLuint* numvectors, GLfloat epsilon)
{
    GLfloat* copies;
    GLuint   copied;
    GLuint   i, j;

    copies = (GLfloat*)malloc(sizeof(GLfloat) * 3 * (*numvectors + 1));
    memcpy(copies, vectors, (sizeof(GLfloat) * 3 * (*numvectors + 1)));

    copied = 1;
    for (i = 1; i <= *numvectors; i++) {
	for (j = 1; j <= copied; j++) {
	    if (_glmEqual(&vectors[3 * i], &copies[3 * j], epsilon)) {
		goto duplicate;
	    }
	}

	/* must not be any duplicates -- add to the copies array */
	copies[3 * copied + 0] = vectors[3 * i + 0];
	copies[3 * copied + 1] = vectors[3 * i + 1];
	copies[3 * copied + 2] = vectors[3 * i + 2];
	j = copied;				/* pass this along for below */
	copied++;

	duplicate:
	/* set the first component of this vector to point at the correct
       index into the new copies array */
	vectors[3 * i + 0] = (GLfloat)j;
    }

    *numvectors = copied-1;
    return copies;
}

/* _glmFindGroup: Find a group in the model
 */
GLMgroup*
	_glmFindGroup(GLMmodel* model, char* name)
{
    GLMgroup* group;

    assert(model);

    group = model->groups;
    while(group) {
	if (!strcmp(name, group->name))
	    break;
	group = group->next;
    }

    return group;
}

/* _glmAddGroup: Add a group to the model
 */
GLMgroup*
	_glmAddGroup(GLMmodel* model, char* name)
{
    GLMgroup* group;

    group = _glmFindGroup(model, name);
    if (!group) {
	group = (GLMgroup*)malloc(sizeof(GLMgroup));
	group->name = strdup(name);
	group->material = 0;
	group->numtriangles = 0;
	group->triangles = NULL;
	group->next = model->groups;
	model->groups = group;
	model->numgroups++;
    }

    return group;
}

/* _glmFindGroup: Find a material in the model
 */
GLuint
	_glmFindMaterial(GLMmodel* model, char* name)
{
    GLuint i;

    for (i = 0; i < model->nummaterials; i++) {
	if (!strcmp(model->materials[i].name, name))
	    goto found;
    }

    /* didn't find the name, so set it as the default material */
    printf("_glmFindMaterial():  can't find material \"%s\".\n", name);
    i = 0;

    found:
    return i;
}


/* _glmDirName: return the directory given a path
 *
 * path - filesystem path
 *
 * The return value should be free'd.
 */
static char*
	_glmDirName(char* path)
{
    char* dir;
    char* s;

    dir = strdup(path);

    s = strrchr(dir, '/');
    if (s)
	s[1] = '\0';
    else
	dir[0] = '\0';

    return dir;
}


/* _glmReadMTL: read a wavefront material library file
 *
 * model - properly initialized GLMmodel structure
 * name  - name of the material library
 */
static GLvoid
	_glmReadMTL(GLMmodel* model, char* name)
{
    FILE* file;
    char* dir;
    char* filename;
    char  buf[128];
    GLuint nummaterials, i;

    dir = _glmDirName(model->pathname);
    filename = (char*)malloc(sizeof(char) * (strlen(dir) + strlen(name) + 1));
    strcpy(filename, dir);
    strcat(filename, name);
    free(dir);

    /* open the file */
    file = fopen(filename, "r");
    if (!file) {
	fprintf(stderr, "_glmReadMTL() failed: can't open material file \"%s\".\n",
		filename);
	exit(1);
    }
    free(filename);

    /* count the number of materials in the file */
    nummaterials = 1;
    while(fscanf(file, "%s", buf) != EOF) {
	switch(buf[0]) {
	case '#':				/* comment */
	    /* eat up rest of line */
	    fgets(buf, sizeof(buf), file);
	    break;
	case 'n':				/* newmtl */
	    fgets(buf, sizeof(buf), file);
	    nummaterials++;
	    sscanf(buf, "%s %s", buf, buf);
	    break;
	default:
	    /* eat up rest of line */
	    fgets(buf, sizeof(buf), file);
	    break;
	}
    }

    rewind(file);

    /* allocate memory for the materials */
    model->materials = (GLMmaterial*)malloc(sizeof(GLMmaterial) * nummaterials);
    model->nummaterials = nummaterials;

    /* set the default material */
    for (i = 0; i < nummaterials; i++) {
	model->materials[i].name = NULL;
	model->materials[i].shininess = 0;
	model->materials[i].diffuse[0] = 0.8;
	model->materials[i].diffuse[1] = 0.8;
	model->materials[i].diffuse[2] = 0.8;
	model->materials[i].diffuse[3] = 1.0;
	model->materials[i].ambient[0] = 0.2;
	model->materials[i].ambient[1] = 0.2;
	model->materials[i].ambient[2] = 0.2;
	model->materials[i].ambient[3] = 1.0;
	model->materials[i].specular[0] = 0.0;
	model->materials[i].specular[1] = 0.0;
	model->materials[i].specular[2] = 0.0;
	model->materials[i].specular[3] = 1.0;
    }
    model->materials[0].name = strdup("default");

    /* now, read in the data */
    nummaterials = 0;
    while(fscanf(file, "%s", buf) != EOF) {
	switch(buf[0]) {
	case '#':				/* comment */
	    /* eat up rest of line */
	    fgets(buf, sizeof(buf), file);
	    break;
	case 'n':				/* newmtl */
	    fgets(buf, sizeof(buf), file);
	    sscanf(buf, "%s %s", buf, buf);
	    nummaterials++;
	    model->materials[nummaterials].name = strdup(buf);
	    break;
	case 'N':
	    fscanf(file, "%f", &model->materials[nummaterials].shininess);
	    /* wavefront shininess is from [0, 1000], so scale for OpenGL */
	    model->materials[nummaterials].shininess /= 1000.0;
	    model->materials[nummaterials].shininess *= 128.0;
	    break;
	case 'K':
	    switch(buf[1]) {
	    case 'd':
		fscanf(file, "%f %f %f",
		       &model->materials[nummaterials].diffuse[0],
		       &model->materials[nummaterials].diffuse[1],
		       &model->materials[nummaterials].diffuse[2]);
		break;
	    case 's':
		fscanf(file, "%f %f %f",
		       &model->materials[nummaterials].specular[0],
		       &model->materials[nummaterials].specular[1],
		       &model->materials[nummaterials].specular[2]);
		break;
	    case 'a':
		fscanf(file, "%f %f %f",
		       &model->materials[nummaterials].ambient[0],
		       &model->materials[nummaterials].ambient[1],
		       &model->materials[nummaterials].ambient[2]);
		break;
	    default:
		/* eat up rest of line */
		fgets(buf, sizeof(buf), file);
		break;
	    }
	    break;
    default:
	    /* eat up rest of line */
	    fgets(buf, sizeof(buf), file);
	    break;
	}
    }
}

/* _glmWriteMTL: write a wavefront material library file
 *
 * model      - properly initialized GLMmodel structure
 * modelpath  - pathname of the model being written
 * mtllibname - name of the material library to be written
 */
static GLvoid
	_glmWriteMTL(GLMmodel* model, char* modelpath, char* mtllibname)
{
    FILE* file;
    char* dir;
    char* filename;
    GLMmaterial* material;
    GLuint i;

    dir = _glmDirName(modelpath);
    filename = (char*)malloc(sizeof(char) * (strlen(dir) + strlen(mtllibname)));
    strcpy(filename, dir);
    strcat(filename, mtllibname);
    free(dir);

    /* open the file */
    file = fopen(filename, "w");
    if (!file) {
	fprintf(stderr, "_glmWriteMTL() failed: can't open file \"%s\".\n",
		filename);
	exit(1);
    }
    free(filename);

    /* spit out a header */
    fprintf(file, "#  \n");
    fprintf(file, "#  Wavefront MTL generated by GLM library\n");
    fprintf(file, "#  \n");
    fprintf(file, "#  GLM library copyright (C) 1997 by Nate Robins\n");
    fprintf(file, "#  email: ndr@pobox.com\n");
    fprintf(file, "#  www:   http://www.pobox.com/~ndr\n");
    fprintf(file, "#  \n\n");

    for (i = 0; i < model->nummaterials; i++) {
	material = &model->materials[i];
	fprintf(file, "newmtl %s\n", material->name);
	fprintf(file, "Ka %f %f %f\n",
		material->ambient[0], material->ambient[1], material->ambient[2]);
	fprintf(file, "Kd %f %f %f\n",
		material->diffuse[0], material->diffuse[1], material->diffuse[2]);
	fprintf(file, "Ks %f %f %f\n",
		material->specular[0],material->specular[1],material->specular[2]);
	fprintf(file, "Ns %f\n", material->shininess);
	fprintf(file, "\n");
    }
}


/* _glmFirstPass: first pass at a Wavefront OBJ file that gets all the
 * statistics of the model (such as #vertices, #normals, etc)
 *
 * model - properly initialized GLMmodel structure
 * file  - (fopen'd) file descriptor
 */
static GLvoid
	_glmFirstPass(GLMmodel* model, FILE* file)
{
    GLuint    numvertices;		/* number of vertices in model */
    GLuint    numnormals;			/* number of normals in model */
    GLuint    numtexcoords;		/* number of texcoords in model */
    GLuint    numtriangles;		/* number of triangles in model */
    GLMgroup* group;			/* current group */
    unsigned  v, n, t;
    char      buf[128];

    /* make a default group */
    group = _glmAddGroup(model, "default");

    numvertices = numnormals = numtexcoords = numtriangles = 0;
    while(fscanf(file, "%s", buf) != EOF) {
	switch(buf[0]) {
	case '#':				/* comment */
	    /* eat up rest of line */
	    fgets(buf, sizeof(buf), file);
	    break;
	case 'v':				/* v, vn, vt */
	    switch(buf[1]) {
	    case '\0':			/* vertex */
		/* eat up rest of line */
		fgets(buf, sizeof(buf), file);
		numvertices++;
		break;
	    case 'n':				/* normal */
		/* eat up rest of line */
		fgets(buf, sizeof(buf), file);
		numnormals++;
		break;
	    case 't':				/* texcoord */
		/* eat up rest of line */
		fgets(buf, sizeof(buf), file);
		numtexcoords++;
		break;
	    default:
		printf("_glmFirstPass(): Unknown token \"%s\".\n", buf);
		exit(1);
		break;
	    }
	    break;
    case 'm':
	    fgets(buf, sizeof(buf), file);
	    sscanf(buf, "%s %s", buf, buf);
	    model->mtllibname = strdup(buf);
	    _glmReadMTL(model, buf);
	    break;
    case 'u':
	    /* eat up rest of line */
	    fgets(buf, sizeof(buf), file);
	    break;
    case 'g':				/* group */
	/* eat up rest of line */
	fgets(buf, sizeof(buf), file);
	sscanf(buf, "%s", buf);
	group = _glmAddGroup(model, buf);
	break;
    case 'f':				/* face */
	v = n = t = 0;
	fscanf(file, "%s", buf);
	/* can be one of %d, %d//%d, %d/%d, %d/%d/%d %d//%d */
	if (strstr(buf, "//")) {
	    /* v//n */
	    sscanf(buf, "%d//%d", &v, &n);
	    fscanf(file, "%d//%d", &v, &n);
	    fscanf(file, "%d//%d", &v, &n);
	    numtriangles++;
	    group->numtriangles++;
	    while(fscanf(file, "%d//%d", &v, &n) > 0) {
		numtriangles++;
		group->numtriangles++;
	    }
	} else if (sscanf(buf, "%d/%d/%d", &v, &t, &n) == 3) {
	    /* v/t/n */
	    fscanf(file, "%d/%d/%d", &v, &t, &n);
	    fscanf(file, "%d/%d/%d", &v, &t, &n);
	    numtriangles++;
	    group->numtriangles++;
	    while(fscanf(file, "%d/%d/%d", &v, &t, &n) > 0) {
		numtriangles++;
		group->numtriangles++;
	    }
	} else if (sscanf(buf, "%d/%d", &v, &t) == 2) {
	    /* v/t */
	    fscanf(file, "%d/%d", &v, &t);
	    fscanf(file, "%d/%d", &v, &t);
	    numtriangles++;
	    group->numtriangles++;
	    while(fscanf(file, "%d/%d", &v, &t) > 0) {
		numtriangles++;
		group->numtriangles++;
	    }
	} else {
	    /* v */
	    fscanf(file, "%d", &v);
	    fscanf(file, "%d", &v);
	    numtriangles++;
	    group->numtriangles++;
	    while(fscanf(file, "%d", &v) > 0) {
		numtriangles++;
		group->numtriangles++;
	    }
	}
	break;

    default:
	/* eat up rest of line */
	fgets(buf, sizeof(buf), file);
	break;
    }
    }

#if 1
    /* announce the model statistics */
    printf(" Vertices: %d\n", numvertices);
    printf(" Normals: %d\n", numnormals);
    printf(" Texcoords: %d\n", numtexcoords);
    printf(" Triangles: %d\n", numtriangles);
    printf(" Groups: %d\n", model->numgroups);
#endif

    /* set the stats in the model structure */
    model->numvertices  = numvertices;
    model->numnormals   = numnormals;
    model->numtexcoords = numtexcoords;
    model->numtriangles = numtriangles;

    /* allocate memory for the triangles in each group */
    group = model->groups;
    while(group) {
	group->triangles = (GLuint*)malloc(sizeof(GLuint) * group->numtriangles);
	group->numtriangles = 0;
	group = group->next;
    }
}

/* _glmSecondPass: second pass at a Wavefront OBJ file that gets all
 * the data.
 *
 * model - properly initialized GLMmodel structure
 * file  - (fopen'd) file descriptor
 */
static GLvoid
	_glmSecondPass(GLMmodel* model, FILE* file)
{
    GLuint    numvertices;		/* number of vertices in model */
    GLuint    numnormals;			/* number of normals in model */
    GLuint    numtexcoords;		/* number of texcoords in model */
    GLuint    numtriangles;		/* number of triangles in model */
    GLfloat*  vertices;			/* array of vertices  */
    GLfloat*  normals;			/* array of normals */
    GLfloat*  texcoords;			/* array of texture coordinates */
    GLMgroup* group;			/* current group pointer */
    GLuint    material;			/* current material */
    GLuint    v, n, t;
    char      buf[128];

    /* set the pointer shortcuts */
    vertices     = model->vertices;
    normals      = model->normals;
    texcoords    = model->texcoords;
    group        = model->groups;

    /* on the second pass through the file, read all the data into the
     allocated arrays */
    numvertices = numnormals = numtexcoords = 1;
    numtriangles = 0;
    material = 0;
    while(fscanf(file, "%s", buf) != EOF) {
	switch(buf[0]) {
	case '#':				/* comment */
	    /* eat up rest of line */
	    fgets(buf, sizeof(buf), file);
	    break;
	case 'v':				/* v, vn, vt */
	    switch(buf[1]) {
	    case '\0':			/* vertex */
		fscanf(file, "%f %f %f",
		       &vertices[3 * numvertices + X],
		       &vertices[3 * numvertices + Y],
		       &vertices[3 * numvertices + Z]);
		numvertices++;
		break;
	    case 'n':				/* normal */
		fscanf(file, "%f %f %f",
		       &normals[3 * numnormals + X],
		       &normals[3 * numnormals + Y],
		       &normals[3 * numnormals + Z]);
		numnormals++;
		break;
	    case 't':				/* texcoord */
		fscanf(file, "%f %f",
		       &texcoords[2 * numtexcoords + X],
		       &texcoords[2 * numtexcoords + Y]);
		numtexcoords++;
		break;
	    }
	    break;
    case 'u':
	    fgets(buf, sizeof(buf), file);
	    sscanf(buf, "%s %s", buf, buf);
	    group->material = material = _glmFindMaterial(model, buf);
	    break;
    case 'g':				/* group */
	/* eat up rest of line */
	fgets(buf, sizeof(buf), file);
	sscanf(buf, "%s", buf);
	group = _glmFindGroup(model, buf);
	group->material = material;
	break;
    case 'f':				/* face */
	v = n = t = 0;
	fscanf(file, "%s", buf);
	/* can be one of %d, %d//%d, %d/%d, %d/%d/%d %d//%d */
	if (strstr(buf, "//")) {
	    /* v//n */
	    sscanf(buf, "%d//%d", &v, &n);
	    T(numtriangles).vindices[0] = v;
	    T(numtriangles).nindices[0] = n;
	    fscanf(file, "%d//%d", &v, &n);
	    T(numtriangles).vindices[1] = v;
	    T(numtriangles).nindices[1] = n;
	    fscanf(file, "%d//%d", &v, &n);
	    T(numtriangles).vindices[2] = v;
	    T(numtriangles).nindices[2] = n;
	    group->triangles[group->numtriangles++] = numtriangles;
	    numtriangles++;
	    while(fscanf(file, "%d//%d", &v, &n) > 0) {
		T(numtriangles).vindices[0] = T(numtriangles-1).vindices[0];
		T(numtriangles).nindices[0] = T(numtriangles-1).nindices[0];
		T(numtriangles).vindices[1] = T(numtriangles-1).vindices[2];
		T(numtriangles).nindices[1] = T(numtriangles-1).nindices[2];
		T(numtriangles).vindices[2] = v;
		T(numtriangles).nindices[2] = n;
		group->triangles[group->numtriangles++] = numtriangles;
		numtriangles++;
	    }
	} else if (sscanf(buf, "%d/%d/%d", &v, &t, &n) == 3) {
	    /* v/t/n */
	    T(numtriangles).vindices[0] = v;
	    T(numtriangles).tindices[0] = t;
	    T(numtriangles).nindices[0] = n;
	    fscanf(file, "%d/%d/%d", &v, &t, &n);
	    T(numtriangles).vindices[1] = v;
	    T(numtriangles).tindices[1] = t;
	    T(numtriangles).nindices[1] = n;
	    fscanf(file, "%d/%d/%d", &v, &t, &n);
	    T(numtriangles).vindices[2] = v;
	    T(numtriangles).tindices[2] = t;
	    T(numtriangles).nindices[2] = n;
	    group->triangles[group->numtriangles++] = numtriangles;
	    numtriangles++;
	    while(fscanf(file, "%d/%d/%d", &v, &t, &n) > 0) {
		T(numtriangles).vindices[0] = T(numtriangles-1).vindices[0];
		T(numtriangles).tindices[0] = T(numtriangles-1).tindices[0];
		T(numtriangles).nindices[0] = T(numtriangles-1).nindices[0];
		T(numtriangles).vindices[1] = T(numtriangles-1).vindices[2];
		T(numtriangles).tindices[1] = T(numtriangles-1).tindices[2];
		T(numtriangles).nindices[1] = T(numtriangles-1).nindices[2];
		T(numtriangles).vindices[2] = v;
		T(numtriangles).tindices[2] = t;
		T(numtriangles).nindices[2] = n;
		group->triangles[group->numtriangles++] = numtriangles;
		numtriangles++;
	    }
	} else if (sscanf(buf, "%d/%d", &v, &t) == 2) {
	    /* v/t */
	    T(numtriangles).vindices[0] = v;
	    T(numtriangles).tindices[0] = t;
	    fscanf(file, "%d/%d", &v, &t);
	    T(numtriangles).vindices[1] = v;
	    T(numtriangles).tindices[1] = t;
	    fscanf(file, "%d/%d", &v, &t);
	    T(numtriangles).vindices[2] = v;
	    T(numtriangles).tindices[2] = t;
	    group->triangles[group->numtriangles++] = numtriangles;
	    numtriangles++;
	    while(fscanf(file, "%d/%d", &v, &t) > 0) {
		T(numtriangles).vindices[0] = T(numtriangles-1).vindices[0];
		T(numtriangles).tindices[0] = T(numtriangles-1).tindices[0];
		T(numtriangles).vindices[1] = T(numtriangles-1).vindices[2];
		T(numtriangles).tindices[1] = T(numtriangles-1).tindices[2];
		T(numtriangles).vindices[2] = v;
		T(numtriangles).tindices[2] = t;
		group->triangles[group->numtriangles++] = numtriangles;
		numtriangles++;
	    }
	} else {
	    /* v */
	    sscanf(buf, "%d", &v);
	    T(numtriangles).vindices[0] = v;
	    fscanf(file, "%d", &v);
	    T(numtriangles).vindices[1] = v;
	    fscanf(file, "%d", &v);
	    T(numtriangles).vindices[2] = v;
	    group->triangles[group->numtriangles++] = numtriangles;
	    numtriangles++;
	    while(fscanf(file, "%d", &v) > 0) {
		T(numtriangles).vindices[0] = T(numtriangles-1).vindices[0];
		T(numtriangles).vindices[1] = T(numtriangles-1).vindices[2];
		T(numtriangles).vindices[2] = v;
		group->triangles[group->numtriangles++] = numtriangles;
		numtriangles++;
	    }
	}
	break;

    default:
	/* eat up rest of line */
	fgets(buf, sizeof(buf), file);
	break;
    }

    }
#if 0
    /* announce the memory requirements */
    printf(" Memory: %d bytes\n",
	   numvertices  * 3*sizeof(GLfloat) +
	   numnormals   * 3*sizeof(GLfloat) * (numnormals ? 1 : 0) +
	   numtexcoords * 3*sizeof(GLfloat) * (numtexcoords ? 1 : 0) +
	   numtriangles * sizeof(GLMtriangle));
#endif
}




/* public functions */

/* glmUnitize: "unitize" a model by translating it to the origin and
 * scaling it to fit in a unit cube around the origin.  Returns the
 * scalefactor used.
 *
 * model - properly initialized GLMmodel structure
 */
GLfloat
	glmUnitize(GLMmodel* model)
{
    GLuint  i;
    GLfloat maxx, minx, maxy, miny, maxz, minz;
    GLfloat cx, cy, cz, w, h, d;
    GLfloat scale;

    assert(model);
    assert(model->vertices);

    /* get the max/mins */
    maxx = minx = model->vertices[3 + X];
    maxy = miny = model->vertices[3 + Y];
    maxz = minz = model->vertices[3 + Z];
    for (i = 1; i <= model->numvertices; i++) {
	if (maxx < model->vertices[3 * i + X])
	    maxx = model->vertices[3 * i + X];
	if (minx > model->vertices[3 * i + X])
	    minx = model->vertices[3 * i + X];

	if (maxy < model->vertices[3 * i + Y])
	    maxy = model->vertices[3 * i + Y];
	if (miny > model->vertices[3 * i + Y])
	    miny = model->vertices[3 * i + Y];

	if (maxz < model->vertices[3 * i + Z])
	    maxz = model->vertices[3 * i + Z];
	if (minz > model->vertices[3 * i + Z])
	    minz = model->vertices[3 * i + Z];
    }

    /* calculate model width, height, and depth */
    w = _glmAbs(maxx) + _glmAbs(minx);
    h = _glmAbs(maxy) + _glmAbs(miny);
    d = _glmAbs(maxz) + _glmAbs(minz);

    /* calculate center of the model */
    cx = (maxx + minx) / 2.0;
    cy = (maxy + miny) / 2.0;
    cz = (maxz + minz) / 2.0;

    /* calculate unitizing scale factor */
    scale = 2.0 / _glmMax(_glmMax(w, h), d);

    /* translate around center then scale */
    for (i = 1; i <= model->numvertices; i++) {
	model->vertices[3 * i + X] -= cx;
	model->vertices[3 * i + Y] -= cy;
	model->vertices[3 * i + Z] -= cz;
	model->vertices[3 * i + X] *= scale;
	model->vertices[3 * i + Y] *= scale;
	model->vertices[3 * i + Z] *= scale;
    }

    return scale;
}

/* glmDimensions: Calculates the dimensions (width, height, depth) of
 * a model.
 *
 * model      - initialized GLMmodel structure
 * dimensions - array of 3 GLfloats (GLfloat dimensions[3])
 */
GLvoid
	glmDimensions(GLMmodel* model, GLfloat* dimensions)
{
    GLuint i;
    GLfloat maxx, minx, maxy, miny, maxz, minz;

    assert(model);
    assert(model->vertices);
    assert(dimensions);

    /* get the max/mins */
    maxx = minx = model->vertices[3 + X];
    maxy = miny = model->vertices[3 + Y];
    maxz = minz = model->vertices[3 + Z];
    for (i = 1; i <= model->numvertices; i++) {
	if (maxx < model->vertices[3 * i + X])
	    maxx = model->vertices[3 * i + X];
	if (minx > model->vertices[3 * i + X])
	    minx = model->vertices[3 * i + X];

	if (maxy < model->vertices[3 * i + Y])
	    maxy = model->vertices[3 * i + Y];
	if (miny > model->vertices[3 * i + Y])
	    miny = model->vertices[3 * i + Y];

	if (maxz < model->vertices[3 * i + Z])
	    maxz = model->vertices[3 * i + Z];
	if (minz > model->vertices[3 * i + Z])
	    minz = model->vertices[3 * i + Z];
    }

    /* calculate model width, height, and depth */
    dimensions[X] = _glmAbs(maxx) + _glmAbs(minx);
    dimensions[Y] = _glmAbs(maxy) + _glmAbs(miny);
    dimensions[Z] = _glmAbs(maxz) + _glmAbs(minz);
}

/* glmScale: Scales a model by a given amount.
 *
 * model - properly initialized GLMmodel structure
 * scale - scalefactor (0.5 = half as large, 2.0 = twice as large)
 */
GLvoid
	glmScale(GLMmodel* model, GLfloat scale)
{
    GLuint i;

    for (i = 1; i <= model->numvertices; i++) {
	model->vertices[3 * i + X] *= scale;
	model->vertices[3 * i + Y] *= scale;
	model->vertices[3 * i + Z] *= scale;
    }
}

/* glmReverseWinding: Reverse the polygon winding for all polygons in
 * this model.  Default winding is counter-clockwise.  Also changes
 * the direction of the normals.
 *
 * model - properly initialized GLMmodel structure
 */
GLvoid
	glmReverseWinding(GLMmodel* model)
{
    GLuint i, swap;

    assert(model);

    for (i = 0; i < model->numtriangles; i++) {
	swap = T(i).vindices[0];
	T(i).vindices[0] = T(i).vindices[2];
	T(i).vindices[2] = swap;

	if (model->numnormals) {
	    swap = T(i).nindices[0];
	    T(i).nindices[0] = T(i).nindices[2];
	    T(i).nindices[2] = swap;
	}

	if (model->numtexcoords) {
	    swap = T(i).tindices[0];
	    T(i).tindices[0] = T(i).tindices[2];
	    T(i).tindices[2] = swap;
	}
    }

    /* reverse facet normals */
    for (i = 1; i <= model->numfacetnorms; i++) {
	model->facetnorms[3 * i + X] = -model->facetnorms[3 * i + X];
	model->facetnorms[3 * i + Y] = -model->facetnorms[3 * i + Y];
	model->facetnorms[3 * i + Z] = -model->facetnorms[3 * i + Z];
    }

    /* reverse vertex normals */
    for (i = 1; i <= model->numnormals; i++) {
	model->normals[3 * i + X] = -model->normals[3 * i + X];
	model->normals[3 * i + Y] = -model->normals[3 * i + Y];
	model->normals[3 * i + Z] = -model->normals[3 * i + Z];
    }
}

/* glmFacetNormals: Generates facet normals for a model (by taking the
 * cross product of the two vectors derived from the sides of each
 * triangle).  Assumes a counter-clockwise winding.
 *
 * model - initialized GLMmodel structure
 */
GLvoid
	glmFacetNormals(GLMmodel* model)
{
    GLuint  i;
    GLfloat u[3];
    GLfloat v[3];

    assert(model);
    assert(model->vertices);

    /* clobber any old facetnormals */
    if (model->facetnorms)
	free(model->facetnorms);

    /* allocate memory for the new facet normals */
    model->numfacetnorms = model->numtriangles;
    model->facetnorms = (GLfloat*)malloc(sizeof(GLfloat) *
					 3 * (model->numfacetnorms + 1));

    for (i = 0; i < model->numtriangles; i++) {
	model->triangles[i].findex = i+1;

	u[X] = model->vertices[3 * T(i).vindices[1] + X] -
	       model->vertices[3 * T(i).vindices[0] + X];
	u[Y] = model->vertices[3 * T(i).vindices[1] + Y] -
	       model->vertices[3 * T(i).vindices[0] + Y];
	u[Z] = model->vertices[3 * T(i).vindices[1] + Z] -
	       model->vertices[3 * T(i).vindices[0] + Z];

	v[X] = model->vertices[3 * T(i).vindices[2] + X] -
	       model->vertices[3 * T(i).vindices[0] + X];
	v[Y] = model->vertices[3 * T(i).vindices[2] + Y] -
	       model->vertices[3 * T(i).vindices[0] + Y];
	v[Z] = model->vertices[3 * T(i).vindices[2] + Z] -
	       model->vertices[3 * T(i).vindices[0] + Z];

	_glmCross(u, v, &model->facetnorms[3 * (i+1)]);
	_glmNormalize(&model->facetnorms[3 * (i+1)]);
    }
}

/* glmVertexNormals: Generates smooth vertex normals for a model.
 * First builds a list of all the triangles each vertex is in.  Then
 * loops through each vertex in the the list averaging all the facet
 * normals of the triangles each vertex is in.  Finally, sets the
 * normal index in the triangle for the vertex to the generated smooth
 * normal.  If the dot product of a facet normal and the facet normal
 * associated with the first triangle in the list of triangles the
 * current vertex is in is greater than the cosine of the angle
 * parameter to the function, that facet normal is not added into the
 * average normal calculation and the corresponding vertex is given
 * the facet normal.  This tends to preserve hard edges.  The angle to
 * use depends on the model, but 90 degrees is usually a good start.
 *
 * model - initialized GLMmodel structure
 * angle - maximum angle (in degrees) to smooth across
 */
GLvoid
	glmVertexNormals(GLMmodel* model, GLfloat angle)
{
    GLMnode*  node;
    GLMnode*  tail;
    GLMnode** members;
    GLfloat*  normals;
    GLuint    numnormals;
    GLfloat   average[3];
    GLfloat   dot, cos_angle;
    GLuint    i, avg;

    assert(model);
    assert(model->facetnorms);

    /* calculate the cosine of the angle (in degrees) */
    cos_angle = cos(angle * M_PI / 180.0);

    /* nuke any previous normals */
    if (model->normals)
	free(model->normals);

    /* allocate space for new normals */
    model->numnormals = model->numtriangles * 3; /* 3 normals per triangle */
    model->normals = (GLfloat*)malloc(sizeof(GLfloat)* 3* (model->numnormals+1));

    /* allocate a structure that will hold a linked list of triangle
     indices for each vertex */
    members = (GLMnode**)malloc(sizeof(GLMnode*) * (model->numvertices + 1));
    for (i = 1; i <= model->numvertices; i++)
	members[i] = NULL;

    /* for every triangle, create a node for each vertex in it */
    for (i = 0; i < model->numtriangles; i++) {
	node = (GLMnode*)malloc(sizeof(GLMnode));
	node->index = i;
	node->next  = members[T(i).vindices[0]];
	members[T(i).vindices[0]] = node;

	node = (GLMnode*)malloc(sizeof(GLMnode));
	node->index = i;
	node->next  = members[T(i).vindices[1]];
	members[T(i).vindices[1]] = node;

	node = (GLMnode*)malloc(sizeof(GLMnode));
	node->index = i;
	node->next  = members[T(i).vindices[2]];
	members[T(i).vindices[2]] = node;
    }

    /* calculate the average normal for each vertex */
    numnormals = 1;
    for (i = 1; i <= model->numvertices; i++) {
	/* calculate an average normal for this vertex by averaging the
       facet normal of every triangle this vertex is in */
	node = members[i];
	if (!node)
	    fprintf(stderr, "glmVertexNormals(): vertex w/o a triangle\n");
	average[0] = 0.0; average[1] = 0.0; average[2] = 0.0;
	avg = 0;
	while (node) {
	    /* only average if the dot product of the angle between the two
	 facet normals is greater than the cosine of the threshold
	 angle -- or, said another way, the angle between the two
	 facet normals is less than (or equal to) the threshold angle */
	    dot = _glmDot(&model->facetnorms[3 * T(node->index).findex],
			  &model->facetnorms[3 * T(members[i]->index).findex]);
	    if (dot > cos_angle) {
		node->averaged = GL_TRUE;
		average[0] += model->facetnorms[3 * T(node->index).findex + 0];
		average[1] += model->facetnorms[3 * T(node->index).findex + 1];
		average[2] += model->facetnorms[3 * T(node->index).findex + 2];
		avg = 1;			/* we averaged at least one normal! */
	    } else {
		node->averaged = GL_FALSE;
	    }
	    node = node->next;
	}

	if (avg) {
	    /* normalize the averaged normal */
	    _glmNormalize(average);

	    /* add the normal to the vertex normals list */
	    model->normals[3 * numnormals + 0] = average[0];
	    model->normals[3 * numnormals + 1] = average[1];
	    model->normals[3 * numnormals + 2] = average[2];
	    avg = numnormals;
	    numnormals++;
	}

	/* set the normal of this vertex in each triangle it is in */
	node = members[i];
	while (node) {
	    if (node->averaged) {
		/* if this node was averaged, use the average normal */
		if (T(node->index).vindices[0] == i)
		    T(node->index).nindices[0] = avg;
		else if (T(node->index).vindices[1] == i)
		    T(node->index).nindices[1] = avg;
		else if (T(node->index).vindices[2] == i)
		    T(node->index).nindices[2] = avg;
	    } else {
		/* if this node wasn't averaged, use the facet normal */
		model->normals[3 * numnormals + 0] =
			model->facetnorms[3 * T(node->index).findex + 0];
		model->normals[3 * numnormals + 1] =
			model->facetnorms[3 * T(node->index).findex + 1];
		model->normals[3 * numnormals + 2] =
			model->facetnorms[3 * T(node->index).findex + 2];
		if (T(node->index).vindices[0] == i)
		    T(node->index).nindices[0] = numnormals;
		else if (T(node->index).vindices[1] == i)
		    T(node->index).nindices[1] = numnormals;
		else if (T(node->index).vindices[2] == i)
		    T(node->index).nindices[2] = numnormals;
		numnormals++;
	    }
	    node = node->next;
	}
    }

    model->numnormals = numnormals - 1;

    /* free the member information */
    for (i = 1; i <= model->numvertices; i++) {
	node = members[i];
	while (node) {
	    tail = node;
	    node = node->next;
	    free(tail);
	}
    }
    free(members);

    /* pack the normals array (we previously allocated the maximum
     number of normals that could possibly be created (numtriangles *
     3), so get rid of some of them (usually alot unless none of the
     facet normals were averaged)) */
    normals = model->normals;
    model->normals = (GLfloat*)malloc(sizeof(GLfloat)* 3* (model->numnormals+1));
    for (i = 1; i <= model->numnormals; i++) {
	model->normals[3 * i + 0] = normals[3 * i + 0];
	model->normals[3 * i + 1] = normals[3 * i + 1];
	model->normals[3 * i + 2] = normals[3 * i + 2];
    }
    free(normals);

    printf("glmVertexNormals(): %d normals generated\n", model->numnormals);
}


/* glmLinearTexture: Generates texture coordinates according to a
 * linear projection of the texture map.  It generates these by
 * linearly mapping the vertices onto a square.
 *
 * model - pointer to initialized GLMmodel structure
 */
GLvoid
	glmLinearTexture(GLMmodel* model)
{
    GLMgroup *group;
    GLfloat dimensions[3];
    GLfloat x, y, scalefactor;
    GLuint i;

    assert(model);

    if (model->texcoords)
	free(model->texcoords);
    model->numtexcoords = model->numvertices;
    model->texcoords=(GLfloat*)malloc(sizeof(GLfloat)*2*(model->numtexcoords+1));

    glmDimensions(model, dimensions);
    scalefactor = 2.0 /
		  _glmAbs(_glmMax(_glmMax(dimensions[0], dimensions[1]), dimensions[2]));

    /* do the calculations */
    for(i = 1; i <= model->numvertices; i++) {
	x = model->vertices[3 * i + 0] * scalefactor;
	y = model->vertices[3 * i + 2] * scalefactor;
	model->texcoords[2 * i + 0] = (x + 1.0) / 2.0;
	model->texcoords[2 * i + 1] = (y + 1.0) / 2.0;
    }

    /* go through and put texture coordinate indices in all the triangles */
    group = model->groups;
    while(group) {
	for(i = 0; i < group->numtriangles; i++) {
	    T(group->triangles[i]).tindices[0] = T(group->triangles[i]).vindices[0];
	    T(group->triangles[i]).tindices[1] = T(group->triangles[i]).vindices[1];
	    T(group->triangles[i]).tindices[2] = T(group->triangles[i]).vindices[2];
	}
	group = group->next;
    }

#if 0
    printf("glmLinearTexture(): generated %d linear texture coordinates\n",
	   model->numtexcoords);
#endif
}

/* glmSpheremapTexture: Generates texture coordinates according to a
 * spherical projection of the texture map.  Sometimes referred to as
 * spheremap, or reflection map texture coordinates.  It generates
 * these by using the normal to calculate where that vertex would map
 * onto a sphere.  Since it is impossible to map something flat
 * perfectly onto something spherical, there is distortion at the
 * poles.  This particular implementation causes the poles along the X
 * axis to be distorted.
 *
 * model - pointer to initialized GLMmodel structure
 */
GLvoid
	glmSpheremapTexture(GLMmodel* model)
{
    GLMgroup* group;
    GLfloat theta, phi, rho, x, y, z, r;
    GLuint i;

    assert(model);
    assert(model->normals);

    if (model->texcoords)
	free(model->texcoords);
    model->numtexcoords = model->numnormals;
    model->texcoords=(GLfloat*)malloc(sizeof(GLfloat)*2*(model->numtexcoords+1));

    /* do the calculations */
    for (i = 1; i <= model->numnormals; i++) {
	z = model->normals[3 * i + 0];	/* re-arrange for pole distortion */
	y = model->normals[3 * i + 1];
	x = model->normals[3 * i + 2];
	r = sqrt((x * x) + (y * y));
	rho = sqrt((r * r) + (z * z));

	if(r == 0.0) {
	    theta = 0.0;
	    phi = 0.0;
	} else {
	    if(z == 0.0)
		phi = 3.14159265 / 2.0;
	    else
		phi = acos(z / rho);

#if WE_DONT_NEED_THIS_CODE
	    if(x == 0.0)
		theta = 3.14159265 / 2.0;	/* asin(y / r); */
	    else
		theta = acos(x / r);
#endif

	    if(y == 0.0)
		theta = 3.141592365 / 2.0;	/* acos(x / r); */
	    else
		theta = asin(y / r) + (3.14159265 / 2.0);
	}

	model->texcoords[2 * i + 0] = theta / 3.14159265;
	model->texcoords[2 * i + 1] = phi / 3.14159265;
    }

    /* go through and put texcoord indices in all the triangles */
    group = model->groups;
    while(group) {
	for (i = 0; i < group->numtriangles; i++) {
	    T(group->triangles[i]).tindices[0] = T(group->triangles[i]).nindices[0];
	    T(group->triangles[i]).tindices[1] = T(group->triangles[i]).nindices[1];
	    T(group->triangles[i]).tindices[2] = T(group->triangles[i]).nindices[2];
	}
	group = group->next;
    }

#if 0
    printf("glmSpheremapTexture(): generated %d spheremap texture coordinates\n",
	   model->numtexcoords);
#endif
}

/* glmDelete: Deletes a GLMmodel structure.
 *
 * model - initialized GLMmodel structure
 */
GLvoid
	glmDelete(GLMmodel* model)
{
    GLMgroup* group;
    GLuint i;

    assert(model);

    if (model->pathname)   free(model->pathname);
    if (model->mtllibname) free(model->mtllibname);
    if (model->vertices)   free(model->vertices);
    if (model->normals)    free(model->normals);
    if (model->texcoords)  free(model->texcoords);
    if (model->facetnorms) free(model->facetnorms);
    if (model->triangles)  free(model->triangles);
    if (model->materials) {
	for (i = 0; i < model->nummaterials; i++)
	    free(model->materials[i].name);
    }
    free(model->materials);
    while(model->groups) {
	group = model->groups;
	model->groups = model->groups->next;
	free(group->name);
	free(group->triangles);
	free(group);
    }

    free(model);
}

/* glmReadOBJ: Reads a model description from a Wavefront .OBJ file.
 * Returns a pointer to the created object which should be free'd with
 * glmDelete().
 *
 * filename - name of the file containing the Wavefront .OBJ format data.
 */
GLMmodel*
	glmReadOBJ(char* filename)
{
    setlocale(LC_NUMERIC, "en_US"); // make sure we don't try to read commas instead of dots with fscanf.
    GLMmodel* model;
    FILE*     file;

    /* open the file */
    file = fopen(filename, "r");
    if (!file) {
	fprintf(stderr, "glmReadOBJ() failed: can't open data file \"%s\".\n",
		filename);
	exit(1);
    }

#if 0
    /* announce the model name */
    printf("Model: %s\n", filename);
#endif

    /* allocate a new model */
    model = (GLMmodel*)malloc(sizeof(GLMmodel));
    model->pathname      = strdup(filename);
    model->mtllibname    = NULL;
    model->numvertices   = 0;
    model->vertices      = NULL;
    model->numnormals    = 0;
    model->normals       = NULL;
    model->numtexcoords  = 0;
    model->texcoords     = NULL;
    model->numfacetnorms = 0;
    model->facetnorms    = NULL;
    model->numtriangles  = 0;
    model->triangles     = NULL;
    model->nummaterials  = 0;
    model->materials     = NULL;
    model->numgroups     = 0;
    model->groups        = NULL;
    model->position[0]   = 0.0;
    model->position[1]   = 0.0;
    model->position[2]   = 0.0;

    /* make a first pass through the file to get a count of the number
     of vertices, normals, texcoords & triangles */
    _glmFirstPass(model, file);

    /* allocate memory */
    model->vertices = (GLfloat*)malloc(sizeof(GLfloat) *
				       3 * (model->numvertices + 1));
    model->triangles = (GLMtriangle*)malloc(sizeof(GLMtriangle) *
					    model->numtriangles);
    if (model->numnormals) {
	model->normals = (GLfloat*)malloc(sizeof(GLfloat) *
					  3 * (model->numnormals + 1));
    }
    if (model->numtexcoords) {
	model->texcoords = (GLfloat*)malloc(sizeof(GLfloat) *
					    2 * (model->numtexcoords + 1));
    }

    /* rewind to beginning of file and read in the data this pass */
    rewind(file);

    _glmSecondPass(model, file);

    /* close the file */
    fclose(file);

    return model;
}

/* glmWriteOBJ: Writes a model description in Wavefront .OBJ format to
 * a file.
 *
 * model    - initialized GLMmodel structure
 * filename - name of the file to write the Wavefront .OBJ format data to
 * mode     - a bitwise or of values describing what is written to the file
 *            GLM_NONE     -  render with only vertices
 *            GLM_FLAT     -  render with facet normals
 *            GLM_SMOOTH   -  render with vertex normals
 *            GLM_TEXTURE  -  render with texture coords
 *            GLM_COLOR    -  render with colors (color material)
 *            GLM_MATERIAL -  render with materials
 *            GLM_COLOR and GLM_MATERIAL should not both be specified.
 *            GLM_FLAT and GLM_SMOOTH should not both be specified.
 */
GLvoid
	glmWriteOBJ(GLMmodel* model, char* filename, GLuint mode)
{
    GLuint    i;
    FILE*     file;
    GLMgroup* group;

    assert(model);

    /* do a bit of warning */
    if (mode & GLM_FLAT && !model->facetnorms) {
	printf("glmWriteOBJ() warning: flat normal output requested "
	       "with no facet normals defined.\n");
	mode &= ~GLM_FLAT;
    }
    if (mode & GLM_SMOOTH && !model->normals) {
	printf("glmWriteOBJ() warning: smooth normal output requested "
	       "with no normals defined.\n");
	mode &= ~GLM_SMOOTH;
    }
    if (mode & GLM_TEXTURE && !model->texcoords) {
	printf("glmWriteOBJ() warning: texture coordinate output requested "
	       "with no texture coordinates defined.\n");
	mode &= ~GLM_TEXTURE;
    }
    if (mode & GLM_FLAT && mode & GLM_SMOOTH) {
	printf("glmWriteOBJ() warning: flat normal output requested "
	       "and smooth normal output requested (using smooth).\n");
	mode &= ~GLM_FLAT;
    }

    /* open the file */
    file = fopen(filename, "w");
    if (!file) {
	fprintf(stderr, "glmWriteOBJ() failed: can't open file \"%s\" to write.\n",
		filename);
	exit(1);
    }

    /* spit out a header */
    fprintf(file, "#  \n");
    fprintf(file, "#  Wavefront OBJ generated by GLM library\n");
    fprintf(file, "#  \n");
    fprintf(file, "#  GLM library copyright (C) 1997 by Nate Robins\n");
    fprintf(file, "#  email: ndr@pobox.com\n");
    fprintf(file, "#  www:   http://www.pobox.com/~ndr\n");
    fprintf(file, "#  \n");

    if (mode & GLM_MATERIAL && model->mtllibname) {
	fprintf(file, "\nmtllib %s\n\n", model->mtllibname);
	_glmWriteMTL(model, filename, model->mtllibname);
    }

    /* spit out the vertices */
    fprintf(file, "\n");
    fprintf(file, "# %d vertices\n", model->numvertices);
    for (i = 1; i <= model->numvertices; i++) {
	fprintf(file, "v %f %f %f\n",
		model->vertices[3 * i + 0],
		model->vertices[3 * i + 1],
		model->vertices[3 * i + 2]);
    }

    /* spit out the smooth/flat normals */
    if (mode & GLM_SMOOTH) {
	fprintf(file, "\n");
	fprintf(file, "# %d normals\n", model->numnormals);
	for (i = 1; i <= model->numnormals; i++) {
	    fprintf(file, "vn %f %f %f\n",
		    model->normals[3 * i + 0],
		    model->normals[3 * i + 1],
		    model->normals[3 * i + 2]);
	}
    } else if (mode & GLM_FLAT) {
	fprintf(file, "\n");
	fprintf(file, "# %d normals\n", model->numfacetnorms);
	for (i = 1; i <= model->numnormals; i++) {
	    fprintf(file, "vn %f %f %f\n",
		    model->facetnorms[3 * i + 0],
		    model->facetnorms[3 * i + 1],
		    model->facetnorms[3 * i + 2]);
	}
    }

    /* spit out the texture coordinates */
    if (mode & GLM_TEXTURE) {
	fprintf(file, "\n");
	fprintf(file, "# %d texcoords\n", model->texcoords);
	for (i = 1; i <= model->numtexcoords; i++) {
	    fprintf(file, "vt %f %f\n",
		    model->texcoords[2 * i + 0],
		    model->texcoords[2 * i + 1]);
	}
    }

    fprintf(file, "\n");
    fprintf(file, "# %d groups\n", model->numgroups);
    fprintf(file, "# %d faces (triangles)\n", model->numtriangles);
    fprintf(file, "\n");

    group = model->groups;
    while(group) {
	fprintf(file, "g %s\n", group->name);
	if (mode & GLM_MATERIAL)
	    fprintf(file, "usemtl %s\n", model->materials[group->material].name);
	for (i = 0; i < group->numtriangles; i++) {
	    if (mode & GLM_SMOOTH && mode & GLM_TEXTURE) {
		fprintf(file, "f %d/%d/%d %d/%d/%d %d/%d/%d\n",
			T(group->triangles[i]).vindices[0],
			T(group->triangles[i]).nindices[0],
			T(group->triangles[i]).tindices[0],
			T(group->triangles[i]).vindices[1],
			T(group->triangles[i]).nindices[1],
			T(group->triangles[i]).tindices[1],
			T(group->triangles[i]).vindices[2],
			T(group->triangles[i]).nindices[2],
			T(group->triangles[i]).tindices[2]);
	    } else if (mode & GLM_FLAT && mode & GLM_TEXTURE) {
		fprintf(file, "f %d/%d %d/%d %d/%d\n",
			T(group->triangles[i]).vindices[0],
			T(group->triangles[i]).findex,
			T(group->triangles[i]).vindices[1],
			T(group->triangles[i]).findex,
			T(group->triangles[i]).vindices[2],
			T(group->triangles[i]).findex);
	    } else if (mode & GLM_TEXTURE) {
		fprintf(file, "f %d/%d %d/%d %d/%d\n",
			T(group->triangles[i]).vindices[0],
			T(group->triangles[i]).tindices[0],
			T(group->triangles[i]).vindices[1],
			T(group->triangles[i]).tindices[1],
			T(group->triangles[i]).vindices[2],
			T(group->triangles[i]).tindices[2]);
	    } else if (mode & GLM_SMOOTH) {
		fprintf(file, "f %d//%d %d//%d %d//%d\n",
			T(group->triangles[i]).vindices[0],
			T(group->triangles[i]).nindices[0],
			T(group->triangles[i]).vindices[1],
			T(group->triangles[i]).nindices[1],
			T(group->triangles[i]).vindices[2],
			T(group->triangles[i]).nindices[2]);
	    } else if (mode & GLM_FLAT) {
		fprintf(file, "f %d//%d %d//%d %d//%d\n",
			T(group->triangles[i]).vindices[0],
			T(group->triangles[i]).findex,
			T(group->triangles[i]).vindices[1],
			T(group->triangles[i]).findex,
			T(group->triangles[i]).vindices[2],
			T(group->triangles[i]).findex);
	    } else {
		fprintf(file, "f %d %d %d\n",
			T(group->triangles[i]).vindices[0],
			T(group->triangles[i]).vindices[1],
			T(group->triangles[i]).vindices[2]);
	    }
	}
	fprintf(file, "\n");
	group = group->next;
    }

    fclose(file);
}

/* glmDraw: Renders the model to the current OpenGL context using the
 * mode specified.
 *
 * model    - initialized GLMmodel structure
 * mode     - a bitwise OR of values describing what is to be rendered.
 *            GLM_NONE     -  render with only vertices
 *            GLM_FLAT     -  render with facet normals
 *            GLM_SMOOTH   -  render with vertex normals
 *            GLM_TEXTURE  -  render with texture coords
 *            GLM_COLOR    -  render with colors (color material)
 *            GLM_MATERIAL -  render with materials
 *            GLM_COLOR and GLM_MATERIAL should not both be specified.
 *            GLM_FLAT and GLM_SMOOTH should not both be specified.
 */
//GLvoid glmDraw(GLMmodel* model, GLuint mode)
//{
//  GLuint i;
//  GLMgroup* group;
//
//  assert(model);
//  assert(model->vertices);
//
//  /* do a bit of warning */
//  if (mode & GLM_FLAT && !model->facetnorms) {
//    printf("glmDraw() warning: flat render mode requested "
//           "with no facet normals defined.\n");
//    mode &= ~GLM_FLAT;
//  }
//  if (mode & GLM_SMOOTH && !model->normals) {
//    printf("glmDraw() warning: smooth render mode requested "
//           "with no normals defined.\n");
//    mode &= ~GLM_SMOOTH;
//  }
//  if (mode & GLM_TEXTURE && !model->texcoords) {
//    printf("glmDraw() warning: texture render mode requested "
//           "with no texture coordinates defined.\n");
//    mode &= ~GLM_TEXTURE;
//  }
//  if (mode & GLM_FLAT && mode & GLM_SMOOTH) {
//    printf("glmDraw() warning: flat render mode requested "
//           "and smooth render mode requested (using smooth).\n");
//    mode &= ~GLM_FLAT;
//  }
//  if (mode & GLM_COLOR && !model->materials) {
//    printf("glmDraw() warning: color render mode requested "
//           "with no materials defined.\n");
//    mode &= ~GLM_COLOR;
//  }
//  if (mode & GLM_MATERIAL && !model->materials) {
//    printf("glmDraw() warning: material render mode requested "
//           "with no materials defined.\n");
//    mode &= ~GLM_MATERIAL;
//  }
//  if (mode & GLM_COLOR && mode & GLM_MATERIAL) {
//    printf("glmDraw() warning: color and material render mode requested "
//           "using only material mode\n");
//    mode &= ~GLM_COLOR;
//  }
//  if (mode & GLM_COLOR)
//    glEnable(GL_COLOR_MATERIAL);
//  if (mode & GLM_MATERIAL)
//    glDisable(GL_COLOR_MATERIAL);
//
//  glPushMatrix();
//  glTranslatef(model->position[0], model->position[1], model->position[2]);
//
//  glBegin(GL_TRIANGLES);
//  group = model->groups;
//  while (group) {
//    if (mode & GLM_MATERIAL) {
//      glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT,
//                   model->materials[group->material].ambient);
//      glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE,
//                   model->materials[group->material].diffuse);
//      glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR,
//                   model->materials[group->material].specular);
//       glMaterialf(GL_FRONT_AND_BACK, GL_SHININESS,
//                  model->materials[group->material].shininess);
//    }
//
//    if (mode & GLM_COLOR) {
//      glColor3fv(model->materials[group->material].diffuse);
//    }
//
//    for (i = 0; i < group->numtriangles; i++) {
//      if (mode & GLM_FLAT)
//        glNormal3fv(&model->facetnorms[3 * T(group->triangles[i]).findex]);
//
//      if (mode & GLM_SMOOTH)
//        glNormal3fv(&model->normals[3 * T(group->triangles[i]).nindices[0]]);
//      if (mode & GLM_TEXTURE)
//        glTexCoord2fv(&model->texcoords[2*T(group->triangles[i]).tindices[0]]);
//      glVertex3fv(&model->vertices[3 * T(group->triangles[i]).vindices[0]]);
//#if 0
//      printf("%f %f %f\n",
//             model->vertices[3 * T(group->triangles[i]).vindices[0] + X],
//             model->vertices[3 * T(group->triangles[i]).vindices[0] + Y],
//             model->vertices[3 * T(group->triangles[i]).vindices[0] + Z]);
//#endif
//
//      if (mode & GLM_SMOOTH)
//        glNormal3fv(&model->normals[3 * T(group->triangles[i]).nindices[1]]);
//      if (mode & GLM_TEXTURE)
//        glTexCoord2fv(&model->texcoords[2*T(group->triangles[i]).tindices[1]]);
//      glVertex3fv(&model->vertices[3 * T(group->triangles[i]).vindices[1]]);
//#if 0
//      printf("%f %f %f\n",
//             model->vertices[3 * T(group->triangles[i]).vindices[1] + X],
//             model->vertices[3 * T(group->triangles[i]).vindices[1] + Y],
//             model->vertices[3 * T(group->triangles[i]).vindices[1] + Z]);
//#endif
//
//      if (mode & GLM_SMOOTH)
//        glNormal3fv(&model->normals[3 * T(group->triangles[i]).nindices[2]]);
//      if (mode & GLM_TEXTURE)
//        glTexCoord2fv(&model->texcoords[2*T(group->triangles[i]).tindices[2]]);
//      glVertex3fv(&model->vertices[3 * T(group->triangles[i]).vindices[2]]);
//#if 0
//      printf("%f %f %f\n",
//             model->vertices[3 * T(group->triangles[i]).vindices[2] + X],
//             model->vertices[3 * T(group->triangles[i]).vindices[2] + Y],
//             model->vertices[3 * T(group->triangles[i]).vindices[2] + Z]);
//#endif
//
//    }
//
//    group = group->next;
//  }
//  glEnd();
//
//  glPopMatrix();
//}

/* glmList: Generates and returns a display list for the model using
 * the mode specified.
 *
 * model    - initialized GLMmodel structure
 * mode     - a bitwise OR of values describing what is to be rendered.
 *            GLM_NONE     -  render with only vertices
 *            GLM_FLAT     -  render with facet normals
 *            GLM_SMOOTH   -  render with vertex normals
 *            GLM_TEXTURE  -  render with texture coords
 *            GLM_COLOR    -  render with colors (color material)
 *            GLM_MATERIAL -  render with materials
 *            GLM_COLOR and GLM_MATERIAL should not both be specified.
 *            GLM_FLAT and GLM_SMOOTH should not both be specified.
 */
//GLuint
//glmList(GLMmodel* model, GLuint mode)
//{
//  GLuint list;
//
//  list = glGenLists(1);
//  glNewList(list, GL_COMPILE);
//  glmDraw(model, mode);
//  glEndList();
//
//  return list;
//}

/* glmWeld: eliminate (weld) vectors that are within an epsilon of
 * each other.
 *
 * model      - initialized GLMmodel structure
 * epsilon    - maximum difference between vertices
 *              ( 0.00001 is a good start for a unitized model)
 *
 */
//GLvoid
//        glmWeld(GLMmodel* model, GLfloat epsilon)
//{
//    GLfloat* vectors;
//    GLfloat* copies;
//    GLuint   numvectors;
//    GLuint   i;

//    /* vertices */
//    numvectors = model->numvertices;
//    vectors    = model->vertices;
//    copies = _glmWeldVectors(vectors, &numvectors, epsilon);

//    printf("glmWeld(): %d redundant vertices.\n",
//           model->numvertices - numvectors - 1);

//    for (i = 0; i < model->numtriangles; i++) {
//        T(i).vindices[0] = (GLuint)vectors[3 * T(i).vindices[0] + 0];
//        T(i).vindices[1] = (GLuint)vectors[3 * T(i).vindices[1] + 0];
//        T(i).vindices[2] = (GLuint)vectors[3 * T(i).vindices[2] + 0];
//    }

//    /* free space for old vertices */
//    free(vectors);

//    /* allocate space for the new vertices */
//    model->numvertices = numvectors;
//    model->vertices = (GLfloat*)malloc(sizeof(GLfloat) *
//                                       3 * (model->numvertices + 1));

//    /* copy the optimized vertices into the actual vertex list */
//    for (i = 1; i <= model->numvertices; i++) {
//        model->vertices[3 * i + 0] = copies[3 * i + 0];
//        model->vertices[3 * i + 1] = copies[3 * i + 1];
//        model->vertices[3 * i + 2] = copies[3 * i + 2];
//    }

//    free(copies);
//}


#if 0
/* normals */
if (model->numnormals) {
    numvectors = model->numnormals;
    vectors    = model->normals;
    copies = _glmOptimizeVectors(vectors, &numvectors);

    printf("glmOptimize(): %d redundant normals.\n",
	   model->numnormals - numvectors);

    for (i = 0; i < model->numtriangles; i++) {
	T(i).nindices[0] = (GLuint)vectors[3 * T(i).nindices[0] + 0];
	T(i).nindices[1] = (GLuint)vectors[3 * T(i).nindices[1] + 0];
	T(i).nindices[2] = (GLuint)vectors[3 * T(i).nindices[2] + 0];
    }

    /* free space for old normals */
    free(vectors);

    /* allocate space for the new normals */
    model->numnormals = numvectors;
    model->normals = (GLfloat*)malloc(sizeof(GLfloat) *
				      3 * (model->numnormals + 1));

    /* copy the optimized vertices into the actual vertex list */
    for (i = 1; i <= model->numnormals; i++) {
	model->normals[3 * i + 0] = copies[3 * i + 0];
	model->normals[3 * i + 1] = copies[3 * i + 1];
	model->normals[3 * i + 2] = copies[3 * i + 2];
    }

    free(copies);
}

/* texcoords */
if (model->numtexcoords) {
    numvectors = model->numtexcoords;
    vectors    = model->texcoords;
    copies = _glmOptimizeVectors(vectors, &numvectors);

    printf("glmOptimize(): %d redundant texcoords.\n",
	   model->numtexcoords - numvectors);

    for (i = 0; i < model->numtriangles; i++) {
	for (j = 0; j < 3; j++) {
	    T(i).tindices[j] = (GLuint)vectors[3 * T(i).tindices[j] + 0];
	}
    }

    /* free space for old texcoords */
    free(vectors);

    /* allocate space for the new texcoords */
    model->numtexcoords = numvectors;
    model->texcoords = (GLfloat*)malloc(sizeof(GLfloat) *
					2 * (model->numtexcoords + 1));

    /* copy the optimized vertices into the actual vertex list */
    for (i = 1; i <= model->numtexcoords; i++) {
	model->texcoords[2 * i + 0] = copies[2 * i + 0];
	model->texcoords[2 * i + 1] = copies[2 * i + 1];
    }

    free(copies);
}
#endif

#if 0
/* look for unused vertices */
/* look for unused normals */
/* look for unused texcoords */
for (i = 1; i <= model->numvertices; i++) {
    for (j = 0; j < model->numtriangles; i++) {
	if (T(j).vindices[0] == i ||
	    T(j).vindices[1] == i ||
	    T(j).vindices[1] == i)
	    break;
    }
}
#endif

